diff --git a/pyren/mod_elm.py b/pyren/mod_elm.py
index 741dddd..a98e78a 100644
--- a/pyren/mod_elm.py
+++ b/pyren/mod_elm.py
@@ -1358,6 +1358,7 @@ class ELM:
             else:
                 return "WRONG RESPONSE"
 
+    # Can be used only with OBDLink based ELM
     def send_can_cfc_caf(self, command):
         if len(command) == 0:
             return
@@ -1418,6 +1419,7 @@ class ELM:
             else:
                 return "WRONG RESPONSE"
     
+    # Can be used only with OBDLink based ELM
     def send_can_cfc(self, command):
 
         command = command.strip().replace(' ', '').upper()